Photoluminescence properties and crystal structure of color-tunable yellow–orange–carroty–red emissive Sr2(1−x)NaxP2O7:xSm3+ phosphors for near-UV/blue light-based white LEDs

• Published in: Journal of materials science. Materials in electronics 2018-11, Vol.29 (21), p.18781-18790
• Main Authors: Liu, Sha-sha, Zhu, Da-chuan, Yang, Ling-xiang, Zhao, Cong, Pu, Yong
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Chromaticity; Color; Crystal structure; Emission spectra; Light emitting diodes; Luminous intensity; Materials Science; Optical and Electronic Materials; Optical properties; Phosphors; Photoluminescence; Quantum efficiency
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-018-0003-3

A series of Sr 2(1−x) Na x P 2 O 7 :xSm 3+ phosphors with adjustable emission have been synthesized via one-step calcination process of the precursors prepared by co-precipitation method successfully. The crystal structure and luminescent properties of the phosphors were analyzed in detail. Because the Sm 3+ could occupy two different types of Sites (Sr 1 and Sr 2 ), the emission spectra of the Sr 2−x P 2 O 7 :xSm 3+ phosphors excited at 402 nm showed an emission band consisting of two symmetrical single bands (Em1 and Em2) in the wavelength range of 580–620 nm with a peak at 599 nm ( 4 G 5/2  →  6 H 7/2 ). The optimal doping concentration of these phosphors was at x = 0.04. The charge compensator Na + ions can not only improve emission luminous intensity and quantum efficiency (QE) of the Sr 2 P 2 O 7 :Sm 3+ , but also change the shape and position of the emission peak at 599 nm. The color tunable wide gamut light can be controlled through properly adjusting the excitation wavelength of obtained samples, covering the yellow, orange, carroty and red chromaticity region, indicating Sr 2(1−x) Na x P 2 O 7 :xSm 3+ phosphors have high absorptions from the near ultraviolet to blue region and can be efficiently excited by commercial NUV and blue LEDs, thus can be used for developing warm white LEDs.